中国主栽双孢蘑菇菌株的DNA多态性

本文以中国双孢蘑菇不同主栽产区的9个具代表性的双孢蘑菇菌株为材料,用20个随机引物对其进行RAPD分析。结果表明,20个随机引物中,有15个随机引物的扩增产物DNA片段表现出明显的多态性,其中每个引物对不同菌株扩增出的DNA片段数目各不相同,而且不同引物扩增出的DNA带谱也不同,差异较大。这15个引物对供试菌株总共扩增出168条DNA片段,其中最大的片段可达6.77kb,最小的DNA片段仪有0.31kb。同时,比较了供试菌株两两间的遗传相似性,发现它们之间的变化不大,其相似系数从0.6891到1.0000,而平均相似系数仅为0.8500,表明供试菌株之间的亲缘关系较近,遗传变异不丰富。另外,采用系统聚类法中的类平均法,对供试菌株相似系数两两间进行聚类分析并生成树状图谱,直观准确地揭示了它们之间的差异。当相似系数为77％时,所有供试菌株都被聚为一大类,说明我国主栽双孢蘑菇菌株的遗传基础较狭窄,可能来源于同一品系,这为进一步开展双孢蘑菇菌种的遗传改良提供了理论依据。

DNA Polymorphism of Major Cultivation Strains of Agaricus bisporus in China

The random amplified polymorphic DNA(RAPD) analysis was conducted with 20 random primers in 9 representative strains of Agaricus bisporus collected from various major cultivation localities in China in this stady. The result revealed that 15 out of 20 random primers were scorable polymorphic ones. The number of scorable DNA fragments derived from each primer amplifying in various strains was different. Of each primer tested, a wide variation in band profiles was observed. In total, 168 band positions were scored (1/0) for all the tested strains. The size of the amplified DNA fragments ranged from 310 to 6770 base pairs. Meanwhile, the genetic similarity between eacli of all the tested strains differed slightly for the similarity coefficient ranged from 0.6891 to 1.0000. A total average coefficient of similarity was only 0.8500. This indicated that kinship was nearer and there was little genetic variation between strains tested. On the other hand, cluster analysis based on coefficient of genetic similarity between the strains tested was carried out by UPGMA. The dendrogram framed by cluster analysis could exactly show difference among them. All the strains tested were divided into one group when coefficient of similarity was 0.77. This conclusion implied that genetic foundation of major cultivation strains of Agaricus bisporus in China was narrow and their origin might be the same. These results provided us with the theoretical basis for deep going genetic improvement research of Agaricus bisporus strains in our country.